Polycarbonate having improved hydrolytic stability

ABSTRACT

Polycarbonates are provided with hydrolytic stability by combining the polycarbonate polymer with a carboxylic acid salt of cadmium. The cadmium salt provides improved hydrolytic stability to both polycarbonates based on diphenols and halogenated diphenols over conventional stabilizers, and does not detrimentally affect other properties such as color stability, haze, initial tensile strength and elongation.

This application is a continuation in part of our copending application Ser. No. 866,881 filed Jan. 4, 1978 now abandoned which itself is a continuation of application Ser. No. 777,205 filed Mar. 14, 1977, now abandoned, which in turn is a continuation of our application Ser. No. 659,316, filed Feb. 19, 1976, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to polycarbonates and more particularly to polycarbonates having improved hydrolytic stability.

2. Description of the Prior Art

Polycarbonates derived from reactions involving organic dihydroxy compounds and carbonic acid derivatives have found extensive commercial application because of their excellent mechanical and physical properties. These thermoplastic polymers are particularly suited for the manufacture of molded products where impact strength, rigidity, toughness, thermal and dimensional stability as well as excellent electrical properties are required.

Further in many applications, especially those requiring extensive service in the presence of heat and light, polycarbonates are used because of their resistance to these constant conditions. The polycarbonates resistance to extensive light and heat is in many instances attributable to stabilizers which prevent deterioration of optical and molecular properties. Among the most extensively used stabilizers are the neutral esters of phosphorous acid including the alkyl and aryl phosphites and the oxetane phosphites. More extensive discussions involving some phosphite stabilizers can be found in U.S. Pat. No. 3,794,629. Although these stabilizers are effective in protecting the polycarbonate from heat and light they cause the polycarbonate to deteriorate, due to hydrolysis, when exposed to water under elevated temperatures.

In some applications polycarbonates are provided with enhanced flame retardant characteristics by using aromatic diols with bromine or chlorine atoms which have a tendency to free radically dissociate and degrade the polycarbonate. To prevent this degradation phosphites have also been added. However, the phosphites, just as in the case of the non-halogenated polycarbonates have a tendency to make the polycarbonate more susceptible to hydrolytic attack.

Thus in accordance with the present invention polycarbonates are provided having improved hydrolytic stability over conventional stabilizers yet with the other desirable properties of the polycarbonate left substantially unmodified.

SUMMARY OF THE INVENTION

A polycarbonate is provided with enhanced hydrolytic stability which is comprised of an effective amount of a carboxylic acid salt of cadmium and a polycarbonate resin.

DETAILED DESCRIPTION OF THE INVENTION

When used herein "polycarbonate resin" means the neat resin without additives; "Polycarbonate" means both the formulated polycarbonate resin with additives therein and also the final molded plastic product.

The polycarbonate resins useful in practice of the invention are those having a weight average molecular weight between 10,00 and 200,000 and more preferably a melt flow rate range of 1 to 24 g/10 min at 300° C. (ASTM 1238) and are produced by reacting di-(monohydroxyaryl)alkanes or dihydroxybenzenes and substituted dihydroxybenzenes with derivatives of the carbonic acids such as carbonic acid diester, phosgene, bis-chloro-carbonic acid esters of di-(monohydroxyaryl)-alkanes and the bis-chloro-carbonic acid esters of the dihydroxybenzenes and the substituted dihydroxybenzenes.

The two aryl residues of the di-(monohydroxyaryl)alkanes applied according to the invention can be alike or different. The aryl residues can also carry substituents which are not capable of reacting in the conversion into polycarbonates, such as halogen atoms or alkyl groups, for example, the methyl, ethyl, propyl or tert-butyl groups. The alkyl residue of the di-(monohydroxyaryl)alkanes linking the two benzene rings can be an open chain or a cycloaliphatic ring and may be substituted if desired, for example by an aryl residue.

Suitable di-(monohydroxyaryl)-alkanes are for example (4,4'-dihydroxy-diphenyl)-methane, 2,2'-(4,4'-dihydroxy-diphenyl)-propane, 1,1-(4,4'-dihydroxy-diphenyl)cyclohexane, 1,1-(4,4'-dihydroxy-3,3'-dimethyl-diphenyl)cyclohexane, 1,1-(2,2'-dihydroxy-4,4'-dimethyl-diphenyl)butane, 2,2-(2,2'-dihydroxy-4,4'-di-tert.-butyl-diphenyl)propane or 1,1'-(4,4'-dihydroxy-diphenyl)-1-phenyl-ethane, furthermore methane derivatives which carry besides two hydroxyaryl groups an alkyl residue with at least two carbon atoms and a second alkyl residue with one or more carbon atoms, such as 2,2-(4,4'-dihydroxy-diphenyl)-butane, 2,2-(4,4'-dihydroxy-diphenyl)-pentane (melting point 149°-150° C.), 3,3-(4,4'-dihydroxy-diphenyl)-pentane, 2,2-(4,4'-dihydroxy-diphenyl)-hexane, 3,3-(4,4'-dihydroxydiphenyl)-hexane, 2,2-(4,4'-dihydroxy-diphenyl)-4-methylpentane, 2,2-(4,4'-dihydroxy-diphenyl)-heptane, 4,4-(4,4'-dihydroxy-diphenyl)-heptane (melting point 148°-149° C.) or 2,2-(4,4'-dihydroxy-diphenyl)-tri-decane. Suitable di-(monohydroxyaryl)-alkanes, the two aryl residues of which are different are, for example, 2,2-(4,4'-dihydroxy-3'-methyl-diphenyl)-propane and 2,2-(4,4'-dihydroxy-3-methyl-3'-isopropyl-diphenyl)-butane. Suitable di-(monohydroxyaryl)-alkanes, the aryl residues of which carry halogen atoms are for instance 2,2-(3,5,3'5'-tetrachloro-4,4'-dihydroxy-diphenyl)-propane, 2,2-(3,5,3'5'-tetrabromo-4,4'-dihydroxy-diphenyl)-propane, (3,3'-dichloro-4,4'-dihydroxy-diphenyl)-methane and 2,2'-dihydroxy-5,5'-difluoro-diphenyl-methane. Suitable di-(monohydroxyaryl)-alkanes, the alkyl residue of which, linking the two benzene rings, is substituted by an aryl residue are for instance (4,4'-dihydroxydiphenyl)-phenyl-methane and 1,1-(4,4'-dihydroxy-diphenyl)-1-phenyl-ethane.

Suitable dihydroxybenzenes and substituted dihydroxybenzenes are hydroquinone, resorcinol, pyrocatecol, methyl hydroquinone and the like. Other suitable dihydroxyaromatic compounds are 4,4'-dihydroxydiphenyl, 2,2'-dihydroxy-diphenyl, dihydroxynaphthalene, dihydroxyanthracene and compounds represented by the structural formula: ##STR1## wherein X is ##STR2##

In order to obtain special properties, mixtures of various di-(monohydroxyaryl)-alkanes can also be used, thus mixed polycarbonate resins are obtained. By far the most useful polycarbonate resins are those based on 4,4'-dihydroxy-diaryl methanes and more particularly bisphenol A [2,2-(4,4'dihydroxy-diphenyl)-propane]. Thus when flame retardant characteristics are to be imparted to the basic polycarbonate resin, a mixture of bisphenol A and tetrabromobisphenol A [2,2-(3,5,3'5'-tetrabromo-4,4'dihydroxy-diphenyl)-propane] is utilized when reacting with phosgene or a like carbonic acid derivative.

The polycarbonates resins are prepared by methods known to those skilled in the art and more particularly by methods disclosed in U.S. Pat. Nos. 3,028,365, 2,999,846, 3,248,414, 3,153,008, 3,215,668, 3,187,065, 2,970,137, 2,991,273 and 2,999,835 all incorporated herein by reference.

In some uses, pigments may be added to the polycarbonate to form opaque colored molded products. The pigments used to opacify and color the polycarbonate are those conventionally known to skilled artisans for use in high molecular weight thermoplastic pigmentation. By far titanium dioxide is the most preferred pigment to opacify and whiten molded articles because of its high index of refraction, extreme whiteness and brightness. However, other white pigments such as lithopone, zinc sulfide, zinc oxide, antimony trioxide, and the like may be used. To impart color (other than white) to the polycarbonate pigments such as red lead, cuprous oxide, cadmium reds, cinnabar, antimony vermilion (red and brown pigments); zinc yellow, chrome yellows and oranges, cadmium yellow, antimony yellow, (orange and yellow pigments); chrome greens, chrome oxide greens (green pigments); cobalt blue, lampblacks, vegetable blacks, animal blacks (black pigments) and the like may be used.

In addition to the inorganic pigments, recited above, organic pigments may be used such as pigment chlorine, lithol fast yellow, touidine red, permanent orange and the like. Dyes may be added to impart color to the polycarbonate such as the phthalocyanies, the anthraquinones and the like.

The cadmium salts homogeneously incorporated in the polycarbonate which are useful in the practice of the invention are those which are soluble in the polycarbonate resin and readily incorporated therein and based on carboxylic acids and cadmium. In particular, cadmium 2-ethylhexanoate, cadmium laurate, cadmium octoate and cadmium acetate have found the most extensive utility for providing increased hydrolytic stability to the polycarbonate in the practice of the invention.

When cadmium 2-ethylhexanoate is used in the practice of the invention preferably a 66 weight percent solid solution of cadmium 2-ethylhexanoate is incorporated into the polycarbonate at a level of 0.01 to 0.1 percent by weight based on the weight of the polycarbonate resin cadmium laurate is also added to the polycarbonate in an amount between 0.01 and 0.1% by weight based on the weight of the polycarbonate resin.

The invention will be further illustrated by way of the following examples.

EXAMPLE I

A polycarbonate resin which was the reaction product of bisphenol A and phosgene having a melt flow at 300° C. of 3 to 6 grams/10 min. (ASTM D1238) was tinted with 0.00093 g of an anthraquinone blue dye per pound of polycarbonate resin and 0.00064 g of an anthraquinone violet blue dye per pound of polycarbonate resin; 0.05 percent by weight, based on the polycarbonate resin of a 66 weight percent solution of cadmium 2-ethylhexanoate was incorporated into the polycarbonate. The polycarbonate resin, the cadmium 2-ethylhexanoate and the tint were tumble blended and then extruded into pellets; 1/8" sample bars were prepared for impact, tensile and elongation testing. Further the impact and tensile bars were tested for hydrolytic stability. The test results for hydrolytic stability are reported on table I. The samples were tested after oven aging at 130° C. for tensile strength and elongation; the results of the oven aging tests are reported on table II. Tests for optical and melt stability were conducted by molding specimens at 520° F. and 700° F. and by aging the polycarbonate at 375° C. The results of the optical and melt stability tests are reported on table III. The effect of hydrolysis on aging the molded samples at 82° C. in water were conducted; the results of these tests are reported on table IV. Oven aging tests at 130° C. were conducted to determine the effect of such aging on optical properties; the results of such tests are reported on table V. In all of the examples the percentage of cadmium 2-ethylhexanoate shown is that of a 66 percent solids solution thereof.

EXAMPLE II-IX

Example I was repeated except that the stabilizer and pigmentation were varied. The following formulations keyed to the specific examples show the constituents of the particular polycarbonate.

    ______________________________________                                         Example                                                                               Formulation                                                             ______________________________________                                         Example                                                                               Polycarbonate resin of Example I                                        II     0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       0.05% phenylneopentyl phosphite                                         Example                                                                               Polycarbonate resin of Example I                                        III    0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       0.08% tris(3-ethyl-3-methylol oxetane) phosphite                        Example                                                                               Polycarbonate resin of Example I                                        IV     0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       1.36g/lb of polycarbonate resin of hydroxy-                                    benzotriazole                                                                  0.05% cadmium 2-ethylhexanoate solution                                 Example                                                                               Polycarbonate resin of Example I                                        V      0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       1.36g/lb of polycarbonate resin of hydroxy-                                    benzotriazole                                                                  0.05% phenylneopentyl phosphite                                         Example                                                                               Polycarbonate resin of Example I                                        VI     0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       1.36g/lb polycarbonate resin of hydroxybenzotriazole                           0.08% tris(3-ethyl-3-methylol oxetane)-phosphite                        Example                                                                               Polycarbonate resin of Example I                                        VII    0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       0.5% the cerotic acid ester of ceryl alcohol                                   1.36g/lb polycarbonate resin of hydroxybenzotriazole                           0.05% cadmium 2-ethylhexanoate solution                                 Example                                                                               Polycarbonate resin of Example I                                        VIII   0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       0.5% the cerotic acid ester of ceryl alcohol                                   1.36g/lb polycarbonate resin of hydroxybenzotriazole                           0.05% phenylneopentyl phosphite                                         Example                                                                               Polycarbonate resin of Example I                                        IX     0.00093g/lb polycarbonate resin of                                             anthraquinone blue dye                                                         0.00064g/lb polycarbonate resin of                                             anthraquinone violet dye                                                       0.5% of the cerotic acid ester of ceryl alcohol                                1.36g/lb of hydroxybenzotriazole                                               0.08% tris(3-ethyl-3-methylol-oxetane) phosphite                        ______________________________________                                    

The cerotic acid ester of ceryl alcohol is incorporated into the polycarbonate as a mold release in accordance with the teachings of U.S. Pat. No. 3,836,499 incorporated herein by reference.

The hydroxybenzotriazole is a stabilizer for resistance to ultraviolet light. The polycarbonates of Examples II through IX were prepared and tested in accordance with Example I. The results of the tests are reported in the following tables.

                                      TABLE I                                      __________________________________________________________________________     EFFECT ON TENSILE, ELONGATION AND IMPACT PROPERTIES                            OF POLYCARBONATES HAVING VARIOUS STABILIZERS                                   THEREIN DURING AGING IN WATER AT 82° C.                                 __________________________________________________________________________                    Stabilizer                                                                           Tensile Yield                                                                         Tensile Ult.                                                                          Elong.                                                                              Elong.                                                                              Impact                            Example                                                                             Stabilizer                                                                               Concn. %                                                                             Str. psi                                                                              Str. psi                                                                              Yield %                                                                             Ult. %                                                                              Ft.-Lbs.                          __________________________________________________________________________                          Control (Unaged)                                          I    cadmium 2-ethyl-                                                                         0.05  9000   9200   8    100  20.68                                  hexanoate                                                                 II   phenylneopentyl                                                                          0.05  9133   9400   8    102  18.91                                  phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  9400   9400   8    100  19.06                             IV   cadium 2-ethyl-                                                                          0.05  8933   9000   8    100  18.34                                  hexanoate                                                                 V    phenylneopentyl                                                                          0.05  9300   9000             17.28                                  phosphite                                                                 VI   oxetane phosphite                                                                        0.08  9867   9867    3-10                                                                               103  17.10                             VII  cadmium 2-ethyl-                                                                         0.05  9300   9617   10   106  19.06                                  hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  9600   9600   11   102  18.25                                  phosphite                                                                 IX   oxetane phosphite                                                                        0.08  9867   9867   11   102  17.51                                                  3 Days                                                    I    cadmium 2-ethyl-                                                                         0.05  9200   9200   6    20-80                                                                               16.95                                  hexanoate                                                                 II   phenylneopentyl                                                                          0.05  9800   9800   6     6- 95                                                                              11.46                                  phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  10100  10100  6     7-45                                                                               15.74                             IV   cadmium 2-ethyl-                                                                         0.05  9800   9800   6    45-90                                                                               12.3                                   hexanoate                                                                 V    phenylneopentyl                                                                          0.05  10000  10000  7    90    2.58                                  phosphite                                                                 VI   oxetane phosphite                                                                        0.08  10500  10500  6      7.45                                                                               2.92                             VII  cadmium 2-ethyl-                                                                         0.05  9600   9600   7     20-105                                                                              2.22                                  hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  10000  10000  7    65    1.97                                  phosphite                                                                 IX   oxetane phosphite                                                                        0.08  10300  10300  5    5     2.09                                                  6 Days                                                    I    cadmium 2-ethyl-                                                                         0.05  9600   9600   6     5-70                                                                               15.61                                  hexanoate                                                                 II   phenylneopentyl                                                                          0.05  9900   9900   5    20-90                                                                                2.54                                  phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  10200  10200  6    8    15.52                             IV   cadmium 2-ethyl-                                                                         0.05  10000  10000  6     35-100                                                                              2.68                                  hexanoate                                                                 V    phenylneopentyl                                                                          0.05  10200  10200  7    40    1.95                                  phosphite                                                                 VI   oxetane phosphite                                                                        0.08  8300   8300   6    7     2.27                             VII  cadmium 2-ethyl-                                                                         0.05  9700   9700   6     6-60                                                                                2.06                                  hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  10200  10200  7    80    1.52                                  phosphite                                                                 IX   oxetane phosphite                                                                        0.08  10600  10600  5    15-60                                                                                1.68                                                  12 Days                                                   I    cadmium 2-ethyl-                                                                         0.05  9500   9500   8    20-95                                                                               15.74                                  hexanoate                                                                 II   phenylneopentyl                                                                          0.05  9900   9900   8    20    1.75                                  phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  10100  10100  8    8    2.1                               IV   cadmium 2-ethyl-                                                                         0.05  4300   4300   4    4    Fail                                   hexanoate                                                                 V    phenylneopentyl                                                                          0.05  4500   4500   4    4    Fail                                   phosphite                                                                 VI   oxetane phosphite                                                                        0.08  1200   1200   <2   <2   Fail                              VII  cadmium 2-ethyl-                                                                         0.05  9600   9600   8     8-35                                                                               Fail                                   hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  5800   5800   4    4    Fail                                   phosphite -IX                                                                            oxetane phosphite                                                                    0.08   3000   3000 2    2 Fail                            __________________________________________________________________________                    Stabilizer                                                                           Tensile Yield                                                                         Tensile Ult.                                                                          Elong.                                                                              Elong.                                                                              Impact                            Example                                                                             Stabilizer                                                                               Concn. %                                                                             Str. psi                                                                              Elong. psi                                                                            Yield psi                                                                           Ult. %                                                                              Ft.-lbs.                          __________________________________________________________________________                          24 Days                                                   I    cadmium 2-ethyl-                                                                         0.05  9800   7300-9800                                                                             5     5-40                                                                                11.3                                  hexanoate                          66% high                               II   phenylneopentyl                                                                          0.05  10150   7300-10200                                                                           5     5-20                                                                               0.6                                    phosphite              67% low     66% high                               III  oxetane phosphite.sup.1                                                                  0.08  --     10567  2         1.6                               IV   cadmium 2-ethyl-                                                                         0.05  --     1900   --   1    Fail                                   hexanoate                                                                 V    phenylneopentyl                                                                          0.05  --     2000   --   1    Fail                                   phosphite                                                                 VI   oxetane phosphite                                                                        0.08  --      800   --   1    Fail                              VII  cadmium 2-ethyl-                                                                         0.05  4400   4400   <1   1    Fail                                   hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  --     1867   --   1    Fail                                   phosphite                                                                 IX   oxetane phosphite                                                                        0.08  --     1200   --   1    Fail                              __________________________________________________________________________      .sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane)phosphite.    

                                      TABLE II                                     __________________________________________________________________________     EFFECT ON TENSILE AND ELONGATION PROPERTIES                                    OF POLYCARBONATES HAVING VARIOUS STABILIZERS                                   THEREIN DURING OVEN AGING AT 130° C.                                                   Stabilizer                                                                           Tensile Yield                                                                         Tensile Ult.                                                                         Elong.                                                                              Elong.                                  Example                                                                             Stabilizer                                                                               Concn. %                                                                             Str. psi                                                                              Str. psi                                                                             Yield %                                                                             Ult. %                                  __________________________________________________________________________                                 Control                                            I    cadmium 2-ethyl-                                                                         0.05   9000   9200 8    100                                          hexanoate                                                                 II   phenylneopentyl                                                                          0.05   8933   9000 8    100                                          phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08   9300   9617 10   106                                     IV   cadmium 2-ethyl-                                                                         0.05   9133   9400 8    102                                          hexanoate                                                                 V    phenylneopentyl                                                                          0.05   9300   9000 8    100                                          phosphite                                                                 VI   oxetane phosphite                                                                        0.08   9600   9600 11   102                                     VII  cadmium 2-ethyl-                                                                         0.05   9400   9400 8    100                                          hexanoate                                                                 VIII phenylneopentyl                                                                          0.05   9867   9867 8    103                                          phosphite                                                                 IX   oxetane phosphite                                                                        0.08   9867   9867 11   102                                                                 3 Days                                             I    cadmium 2-ethyl-                                                                         0.05  10600  10600 8    75                                           hexanoate                                                                 II   phenylneopentyl                                                                          0.05  10600  10600 8    90                                           phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  --     --    --   --                                      IV   cadmium 2-ethyl-                                                                         0.05  11000  11000 8     30-105                                      hexanoate                                                                 V    phenylneopentyl                                                                          0.05  11000  11000 8    10-70                                        phosphite                                                                 VI   oxetane phosphite                                                                        0.08  11000  11000 8     40-105                                 VII  cadmium 2-ethyl-                                                                         0.05  11400  11400 8    20                                           hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  11300  11300 8    25                                           phosphite                                                                 IX   oxetane phosphite                                                                        0.08  11200  11200 8    10-55                                                               6 Days                                             I    cadmium 2-ethyl-                                                                         0.05  11000  11000 9     30-100                                      hexanoate                                                                 II   phenylneopentyl                                                                          0.05   7666  11033 9    42                                           phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08   8000  11000 9    90                                      IV   cadmium 2-ethyl-                                                                         0.05   8000  11433 10   20-50                                        hexanoate                                                                 V    phenylneopentyl                                                                          0.05   8033  11466 9    45                                           phosphite                                                                 VI   oxetane phosphite                                                                        0.08   7966  11200 9     35-105                                 VII  cadmium 2-ethyl-                                                                         0.05  11933  11933 11   14                                           hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  10400  11266 10   20                                           phosphite                                                                 IX   oxetane phosphite                                                                        0.08   8233  11233 8    25-70                                                               12 Days                                            I    cadmium 2-ethyl-                                                                         0.05  11300   11300                                                                               7    30-75                                        hexanoate                                                                 II   phenylneopentyl                                                                          0.05  11400  11400 8    20                                           phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  11400  11400 8    10-85                                   IV   cadmium 2-ethyl-                                                                         0.05  11500  11500 7    10-75                                        hexanoate                                                                 V    phenylneopentyl                                                                          0.05  11500  11500 8    10-50                                        phosphite                                                                 VI   oxetane phosphite                                                                        0.08  12000  12000 8    10-50                                   VII  cadmium 2-ethyl-                                                                         0.05  11800  11800 7    38                                           hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  11500  11500 7    22                                           phosphite                                                                 IX   oxetane phosphite                                                                        0.08  11800  11800 8    10-25                                                               24 Days                                            I    cadmium 2-ethyl-                                                                         0.05  10800  10800 8    88                                           hexanoate                                                                 II   phenylneopentyl                                                                          0.05  10800  10800 8    15                                           phosphite                                                                 III  oxetane phosphite.sup.1                                                                  0.08  10400  10400 8    45                                      IV   cadmium 2-ethyl-                                                                         0.05  10900  10900 8     50-105                                      hexanoate                                                                 V    phenylneopentyl                                                                          0.05  10900  10900 7    40-85                                        phosphite                                                                 VI   oxetane phosphite                                                                        0.08  11100  11100 8    11-75                                   VII  cadmium 2-ethyl-                                                                         0.05  11200  11200 7     7-75                                        hexanoate                                                                 VIII phenylneopentyl                                                                          0.05  11600  11600 8    11                                           phosphite                                                                 IX   oxetane phosphite                                                                        0.08  11400  11400 8    12                                      __________________________________________________________________________      .sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane)phosphite.    

                                      TABLE III                                    __________________________________________________________________________     OPTICAL AND MELT STABILITY PROPERTIES OF POLYCARBONATE USING VARIOUS           STABILIZERS                                                                                                   700° F.                                               Stabilizer                                                                           520° F. Molding                                                                     Molding                                                                               Irradiation                                                                           Melt Stability                    Example                                                                             Stabilizer                                                                             Concn. %                                                                             Y %                                                                               YI  % Haze                                                                              Y %                                                                               YI  Y %                                                                               YI  at 375° C. APHA            __________________________________________________________________________                                                  color                             I    cadmium 2-                                                                             0.05  84.31                                                                             0.68                                                                               1.06 84.79                                                                             2.38                                                                               83.89                                                                             10.43                                                                              900                                    ethylhexanoate                                                            II   phenyl- 0.05  84.85                                                                             1.49                                                                               1.18 83.70                                                                             2.88                                                                               84.35                                                                             12.09                                                                              800-900                                neopentyl                                                                      phosphite                                                                 III  oxetane 0.08  85.26                                                                             -0.86    85.61                                                                             -0.41                                                                              84.20                                                                             9.49                                                                               >1000                                  phosphite.sup.1                                                           IV   cadmium 2-                                                                             0.05  84.32                                                                             1.10                                                                               1.2  84.36                                                                             3.17                                                                               83.15                                                                             4.65                                                                               >1000                                  ethylhexanoate                                                            V    phenyl- 0.05  85.32                                                                             1.51                                                                               1.2  85.28                                                                             3.41                                                                               84.33                                                                             6.06                                                                               >1000                                  neopentyl                                                                      phosphite                                                                 VI   oxetane 0.08  85.23                                                                             -0.45                                                                              1.0  84.01                                                                             3.49                                                                               84.42                                                                             3.50                                                                               >1000                                  phosphite                                                                 VII  cadmium 2-                                                                             0.05  80.19                                                                             2.53                                                                               1.08 79.82                                                                             5.22                                                                               80.99                                                                             6.09                                                                               >>1000                                 ethylhexanoate                                                            VIII phenyl- 0.05  84.59                                                                             0.22                                                                               1.20 83.98                                                                             2.18                                                                               84.09                                                                             4.35                                                                               >>1000                                 neopentyl                                                                      phosphite                                                                 IX   oxetane 0.08  84.83                                                                             -0.96                                                                              1.20 82.84                                                                             5.06                                                                               83.78                                                                             3.13                                                                               >>1000                                 phosphite                                                                 __________________________________________________________________________      .sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane) phosphite.   

                  TABLE IV                                                         ______________________________________                                         EFFECT ON OPTICAL PROPERTIES OF                                                POLYCARBONATE HAVING VARIOUS STABILIZERS                                       ON AGING IN WATER AT 82° C.                                             Ex-                                                                            ample Stabilizer    Concn.   Y %  YI    Haze %                                 ______________________________________                                                            Unaged                                                      I     cadmium 2-ethyl-                                                                             (0.05%)  84.31                                                                               0.68  1.06                                         hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  84.85                                                                               1.49  1.18                                         phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.26                                                                               -0.86                                        IV    cadmium 2-ethyl-                                                                             (0.05%)  84.32                                                                               1.10  1.2                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  85.32                                                                               1.51  1.2                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.23                                                                               -0.45 1.0                                                       3 Days                                                      I     cadmium 2-ethyl-                                                                             (0.05%)  83.91                                                                               1.20  1.70                                         hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  84.82                                                                               1.78  1.0                                          phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.09                                                                               -0.81 2.0                                    IV    cadmium 2-ethyl-                                                                             (0.05%)  83.97                                                                               1.19  3.0                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  84.66                                                                               1.87  1.6                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.22                                                                               -0.59 1.4                                                       6 Days                                                      I     cadmium 2-ethyl-                                                                             (0.05%)  84.86                                                                               1.29  1.60                                         hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  85.72                                                                               2.08  1.7                                          phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.99                                                                               - 0.37                                                                               1.6                                    IV    cadmium 2-ethyl-                                                                             (0.05%)  84.85                                                                               1.47  1.5                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  84.80                                                                               1.97  1.9                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.72                                                                               -0.27 1.7                                                       12 Days                                                     I     cadmium 2-ethyl-                                                                             (0.05%)  84.35                                                                               1.23  1.16                                         hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  85.15                                                                               2.12  1.62                                         phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.32                                                                               -0.54 1.77                                   IV    cadmium 2-ethyl-                                                                             (0.05%)  --   --    --                                           hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  84.96                                                                               2.06  1.52                                         phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.22                                                                               -0.38 0.84                                                      24 Days                                                     I     cadmium 2-ethyl-                                                                             (0.05%)  83.98                                                                               1.56  3.1                                          hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  83.95                                                                               3.45  4.7                                          phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  84.66                                                                               0.62  5.1                                    IV    cadmium 2-ethyl-                                                                             (0.05%)  83.39                                                                               1.60  2.4                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  83.64                                                                               4.21  4.9                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  84.53                                                                               0.80  3.3                                    ______________________________________                                          .sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane) phosphite.   

                  TABLE V                                                          ______________________________________                                         EFFECT ON OPTICAL PROPERTIES OF                                                POLYCARBONATE WITH VARIOUS STABILIZERS                                         DURING OVEN AGING AT 130° C.                                            Ex-                                                                            ample Stabilizer    Concn.   Y %  YI    Haze %                                 ______________________________________                                                            Unaged                                                      I     cadmium 2-ethyl-                                                                             (0.05%)  84.31                                                                               0.68  1.06                                         hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  84.85                                                                               1.49  1.18                                         phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.26                                                                               -0.86 1.42                                   IV    cadmium 2-ethyl-                                                                             (0.05%)  84.32                                                                               1.10  1.2                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  85.32                                                                               1.51  1.2                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.23                                                                               -0.45 1.0                                                       3 Days                                                      I     cadmium 2-ethyl-                                                                             (0.05%)  84.17                                                                               1.35  1.13                                         hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  84.62                                                                               2.00  1.48                                         phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.49                                                                               -0.73 1.01                                   IV    cadmium 2-ethyl-                                                                             (0.05%)  83.63                                                                               1.48  1.70                                         hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  84.92                                                                               2.01  1.21                                         phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.07                                                                               -0.64 1.32                                                      6 Days                                                      I     cadmium 2-ethyl-                                                                             (0.05%)  84.17                                                                               1.51  1.2                                          hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  83.05                                                                               2.27  1.6                                          phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  85.48                                                                               -0.69 1.4                                    IV    cadmium 2-ethyl-                                                                             (0.05%)  84.05                                                                               1.61  1.9                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  84.74                                                                               2.28  1.8                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  85.16                                                                               -0.54 1.3                                                       12 Days                                                     I     cadmium 2-ethyl-                                                                             (0.05%)  82.88                                                                               2.02  --                                           hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  83.64                                                                               3.09  --                                           phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  84.37                                                                               -0.76 --                                     IV    cadmium 2-ethyl-                                                                             (0.05%)  82.89                                                                               2.17  --                                           hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  82.69                                                                               4.03  --                                           phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  83.78                                                                               -0.33 --                                                        24 Days                                                     I     cadmium 2-ethyl-                                                                             (0.05%)  82.86                                                                               2.56  2.7                                          hexanoate                                                                II    phenylneopentyl                                                                              (0.05%)  80.97                                                                               5.87  3.5                                          phosphite                                                                III   oxetane phosphite.sup.1                                                                      (0.08%)  84.20                                                                               3.89  2.8                                    IV    cadmium 2-ethyl-                                                                             (0.05%)  82.01                                                                               3.21  3.4                                          hexanoate                                                                V     phenylneopentyl                                                                              (0.05%)  79.66                                                                               8.49  3.4                                          phosphite                                                                VI    oxetane phosphite                                                                            (0.08%)  83.71                                                                               0.50  3.9                                    ______________________________________                                          .sup.1 oxetane phosphite is tris(3ethyl-3-methylol oxetane) phosphite.   

In table I the data show the cadmium 2-ethylhexanoate stabilized polycarbonate to have improved elongation and impact properties over polycarbonate formulated with conventional stabilizers after aging under hydrolyzing conditions.

In table II the data shows no reduction in oven heat aging properties using cadmium 2-ethylhexanoate.

In table III the data demonstrate that cadmium 2-ethylhexanoate imparts substantially similar optical and melt stabilities to those obtained using other commercial stabilizers. The samples prepared for table III were molded at two different temperatures 520° F. and 700° F. The variable Y is a measure of brightness and is better with the higher value. YI is the yellowness index, the closer the number is to zero the better the color of the polycarbonate article. Irradiation designates the brightness and yellowness after 310 hrs. after exposure of the polycarbonate article to sunlamp light. The samples for irradiation testing were molded between 540° and 570° F.

As is demonstrated by the above examples, cadmium organic salts provide enhanced hydrolytic stability to polycarbonates over conventional stabilizer without detrimentally effecting the other desirable physical properties for which polycarbonates are used.

EXAMPLE X

A polycarbonate resin which was the reaction product of bisphenol A and phosgene having a melt flow rate at 300° C. of 6 to 12 g/10 min (ASTM 1238) was tumble blended with a copolycarbonate resin based on bisphenol A and tetrabromobisphenol A having 10 percent by weight bromine therein. The blended resin had a melt flow rate at 300° C. of 6 to 12 g/10 min. (ASTM 1238). Sufficient copolymer was used to impart 5% bromine to the total polycarbonate mixture. 0.1 percent by weight based on the weight of total polycarbonate and copolycarbonate resin of a 66% cadmium 2-ethylhexanoate solution was also tumble blended with the resins. The tumble blend was extruded and cut into pellets. The pellets were molded and tested for impact half-life testing. The impact half-life durability is the time taken during aging at 70° F. and 100% relative humidity for the sample to reach one-half of its original impact strength. The test results are reported on Table VI.

EXAMPLES XI and XII

Example X was repeated substituting the conventional stabilizers distearyl pentaerythritol diphosphite (Example XI) and tri (mixed mono and dinonyl phenyl) phosphites (Example XII). Test results are reported on Table VI.

EXAMPLE XIII

Example X was repeated except no stabilizer was added to the polycarbonate. Test results are reported on Table VI.

                  TABLE VI                                                         ______________________________________                                         IMPACT STRENGTH HALF-LIFE ON AGING AT 70° C.                            WITH 100% RELATIVE HUMIDITY                                                                             Stabilizer                                                                              Half Life                                    Example   Stabilizer     Concn.   (Days)                                       ______________________________________                                         X         cadmium 2-ethyl-                                                                              0.1      65                                                     hexanoate                                                            XI        distearyl pentaery-                                                                           0.1      48.3                                                   thritol diphosphite                                                  XII       tri (mixed mono and                                                                           0.1      56.8                                                   dinonyl phenyl)                                                                phosphites                                                           XIII                              87.1                                         ______________________________________                                    

As is demonstrated by Table VI cadmium 2-ethylhexanoate provides improved hydrolytic stability over conventional polycarbonate stabilizers. However, the cadmium 2-ethylhexanoate stabilized polycarbonate is worse in hydrolytic stability than the neat resin. It is necessary to add a stabilizer to the polycarbonate to provide protection from heat and light. The cadmium salts of the invention provide this protection to halogenated polycarbonate resins while imparting improved hydrolytic stability over conventional stabilizers.

                  TABLE VII                                                        ______________________________________                                         CONCENTRATION OF ADDITIVES IN PC FOR                                           COMPARATIVE TESTING OF RETENTION OF                                            OVERALL PROPERTIES DURING AGING                                                ______________________________________                                                                     Molecular                                                                               Molecular                                                   Wt % PC   Formula  Wt                                        ______________________________________                                         1.  Cadmium       0.05      C.sub.16 H.sub.30 O.sub.4 Cd                                                            398.74                                        2-ethylhexanoate                                                           2.  Cadmium Octoate                                                                              0.033     C.sub.16 H.sub.30 O.sub.4 Cd                                                            398.74                                    3.  Cadmium Laurate                                                                              0.042     C.sub.24 H.sub.46 O.sub.4 Cd                                                            510.95                                    4.  Cadmium Valerate                                                                             0.026     C.sub.10 H.sub.18 O.sub.4 Cd                                                            314.58                                    5.  Cadmium Myristate                                                                            0.047     C.sub.28 H.sub.54 O.sub.4 Cd                                                            567.05                                    6.  Cadmium Palmitate                                                                            0.052     C.sub.32 H.sub.62 O.sub.4 Cd                                                            623.16                                    7.  Cadmium Stearate                                                                             0.056     C.sub.36 H.sub.70 O.sub.4 Cd                                                            679.32                                    8.  Cadmium Acetate                                                                              0.015     C.sub.4 H.sub.6 O.sub.4 Cd                                                              230.49                                    9.  Zinc Octoate  0.035     C.sub.16 H.sub.30 O.sub.4 Zn                                                            351.77                                    5.9 g of cadmium octoate was mixed with 4.1 g of phenyl diphenyl               phosphinite* and the combined mixture was heated to 100° C. for 1       hour. This mixture was used in compounding with polycarbonate.                 10. 0.10% of a mixture of cadmium octoate and phenyl diphenyl                  phosphinite (in 5.9/4.1 ratio)                                                 11. 0.30% of a mixture of cadmium octoate and phenyl diphenyl                  phosphinite (in 5.9/4.1 ratio)                                                 12. The polycarbonate resin (MERLON M-50) which was utilized                   for comparative testing was the reaction product of bisphenol A                and phosgene having a melt flow at 300° C. of 3 to 6 grams/10           min.                                                                           (ASTM D-1238) and having a natural color of 7.5. The additives                 (1-11 above) were incorporated into the polycarbonate using a                  dry blend/extrusion compounding technique.                                     The properties studied for comparison of effectiveness were:                   (a) Impact retention at 105° C. (dry air aging) and at 82°       C. (180° F.)                                                            aging in water;                                                                (b) Critical thickness property loss during dry air aging at 105°       C.                                                                             and water aging at 82° C. (180° F.);                             (c) Retention of tensile properties at 130° C. (dry air aging) and      at                                                                             82° C. (aging in water);                                                (d) Color retention between moldings at 520° F. and 700°         F.;                                                                            (e) Discoloration (measured by yellowness index changes) during dry            air aging at 130° C.                                                    13. All of the additives were compounded with polycarbonate at the             same mol percent level.                                                        ______________________________________                                          *Phenyl diphenyl phosphinite was prepared from the reaction of phenyl          dichloro                                                                       phosphine and phenol in presence of TEA. The crude product obtained was        redistilled.                                                             

                                      TABLE VIII                                   __________________________________________________________________________     EFFECT ON IMPACT PROPERTIES (NOTCHED) OF M-50 COMPOUNDED                       WITH VARIOUS ADDITIVES DURING OVEN AGING AT 130° C. AND WATER           AGING AT 82° C.                                                                 Cadmium                                    Cadmium Octoate/                    2-ethyl-                                                                             Cadmium                                                                              Cadmium                                                                              Cadmium                                                                             Cadmium                                                                             Cadmium                                                                             Cadmium                                                                             Cadmium                                                                             Phenyl diphenyl                     hexanoate                                                                            Laurate                                                                              Octoate                                                                              Valerate                                                                            Stearate                                                                            Palmitate                                                                           Acetate                                                                             Myristate                                                                           phosphinite                 __________________________________________________________________________     Additive Wt %                                                                          0.05  0.042 0.033 0.026                                                                               0.056                                                                               0.052                                                                               0.015                                                                               0.047                                                                               0.059/                                                                               0.177/                                                                   0.041 0.122                 Impact                                                                         Properties                                                                     Aged in Oven                                                                   at 105° C.                                                              1/8" Notched                                                                   Izod ft lbs/in                                                                 (0 hr)  17.32                                                                             17.45                                                                             17.61                                                                             17.99                                                                             17.98                                                                             17.33                                                                             17.58                                                                               17.58                                                                               17.13                                                                               17.40                                                                               16.87                                                                               14.51                                                                             17.50                                                                             13.30                                                                             16.17              (8 hrs) 17.76                                                                             -- 17.74                                                                             -- 17.42                                                                             -- 12.44                                                                               --   2.67 --   2.10 2.41                                                                              -- 1.67                                                                              --                 (16 hrs)                                                                               17.69                                                                             -- 17.37                                                                             -- 13.25                                                                             -- 7.37 --   2.09 --   1.99 1.92                                                                              -- 1.51                                                                              --                 (24 hrs)                                                                               -- 16.86                                                                             -- 17.52                                                                             -- 16.99                                                                             --   7.76 --   17.12                                                                               --   -- 1.89                                                                              -- 1.17               (32 hrs)                                                                               17.24                                                                             -- 17.27                                                                             -- 12.36                                                                             -- 2.18 --   2.09 --   1.63 1.73                                                                              -- -- --                 (64 hrs)                                                                               11.94                                                                             -- 7.77                                                                              -- 2.20                                                                              -- 1.84 --   1.84 --   1.42 1.63                                                                              -- -- --                 (72 hrs)                                                                               -- 16.82                                                                             -- 12.30                                                                             -- 2.86                                                                              --   2.00 --   7.38 --   -- 1.66                                                                              -- 1.22               (128 hrs)                                                                              12.46                                                                             -- 2.57                                                                              -- 1.83                                                                              -- 1.60 --   1.70 --   --   -- -- -- --                 (144 hrs)                                                                              -- 3.48                                                                              -- 3.38                                                                              -- 2.43                                                                              --   1.84 --   2.20 --   -- 1.50                                                                              -- 1.14               (288 hrs)                                                                              -- 1.99                                                                              -- 2.07                                                                              -- 1.84                                                                              --   1.66 --   1.97 --   -- 1.60                                                                              -- 1.11               (670 hrs)                                                                              -- -- -- -- -- -- --   --   --   --   --   -- -- -- --                 Water aged                                                                     at 82° C.                                                               1/8" Notched                                                                   Izod ft lbs/in                                                                 (0 day) 17.32                                                                             17.45                                                                             17.61                                                                             17.99                                                                             17.98                                                                             17.33                                                                             17.58                                                                               17.58                                                                               17.13                                                                               17.40                                                                               16.87                                                                               14.51                                                                             17.50                                                                             13.30                                                                             16.17              (1 day) 17.71                                                                             17.84                                                                             13.18                                                                             18.06                                                                             3.39                                                                              1.76                                                                              7.95 1.30 1.36 17.80                                                                               1.07 1.34                                                                              16.40                                                                             0.21                                                                              1.50               (3 days)                                                                               17.84                                                                             12.43                                                                             17.11                                                                             17.32                                                                             0.60                                                                              1.15                                                                              1.02 0.94 1.36 19.27                                                                               0.60 0.58                                                                              2.86                                                                              0.24                                                                              0.99               (6 days)                                                                               18.08                                                                             12.66                                                                             17.42                                                                             17.69                                                                             1.02                                                                              0.94                                                                              --   0.58 --   2.20 --   -- 2.61                                                                              -- 0.79               (12 days)                                                                              17.53                                                                             12.25                                                                             17.24                                                                             12.48                                                                             0.55                                                                              0.81                                                                              --   0.53 --   1.86 --   -- -- -- 0.51               (24 days)                                                                              -- 12.76                                                                             -- 8.02                                                                              -- 0.53                                                                              --   --   --   1.55 --   -- -- -- --                 __________________________________________________________________________

                                      TABLE IX                                     __________________________________________________________________________     EFFECT ON CRITICAL THICKNESS PROPERTIES OF M-50 COMPOUNDED                     WITH VARIOUS ADDITIVES DURING OVEN AGING AT 130° C. AND WATER           AGING AT 82° C.                                                                     Cadmium                             Cadmium Octoate/                           2-ethyl-                                                                             Cadmium                                                                              Cadmium                                                                              Cadmium                                                                              Cadmium                                                                              Cadmium                                                                              Phenyl diphenyl                            hexanoate                                                                            Laurate                                                                              Octoate                                                                              Valerate                                                                             Palmitate                                                                            Myristate                                                                            phosphinite                    __________________________________________________________________________     Additive Wt %                                                                               0.05 0.042 0.033 0.026 0.052 0.047 0.059/                                                                              0.177/                                                                    0.041                                                                               0.122                     Oven Aging at 105° C.                                                    0 hr       212   207   202   187   182   182   167  152                        4 hrs      202   202   145   135   135   120   110  110                        8 hrs      150   160   137   132   122   112   112  <100                       16 hrs     145   142   122   122   122   112   112  <100                       32 hrs     142   137   135   122   122   102   102                             64 hrs     132   125   115   112   105   100   <100                           128 hrs     132   122   102   102   102   100   <100                           Aged at 82° C. in H.sub.2 O                                              0 day      212   207   202   187   182   182   167  152                        1 day      192   192   <120  <120  <100  <100  <100 <100                       3 days     177   165   <100  105   <100  <100  <100 <100                       6 days     177   172                                                          12 days     172   167                                                          __________________________________________________________________________

                                      TABLE X                                      __________________________________________________________________________     Water Aged (82° C.) Tensile Properties of Polycarbonates                Compounded with Various Cadmium Salts and Zinc Salts of Organic Acids                                Cadmi-                                                                         um 2-                                                                              Cadmi-             Cadmium Octoate/                                        ethyl-                                                                             um                 Phenyl                                                  hexa-                                                                              Octo-                                                                              Zinc Cadmium                                                                             Cadmium                                                                             Diphenyl    Cadmium               Aged  Additive        noate                                                                              ate Octoate                                                                             Laurate                                                                             Acetate                                                                             Phosphinite Stearate              __________________________________________________________________________           Additive Wt. %  0.05                                                                               0.033                                                                              0.035                                                                               0.041                                                                               0.015                                                                               0.059/0.041                                                                          0.177/0.123                                                                          0.059/.041            0 Days                                                                               Initial Tensile Properties                                               US    Tensile Strength at Yield, psi                                                                 9300                                                                               9,300                                                                              9,000                                                                               9300 9,100                                                                               9,200 9,200 9,300                 SI    Tensile Strength at Yield, MPa                                                                 64.1                                                                               64.1                                                                               62   64.1 62.7 63.4  63.4  64.1                  US    Ultimate Tensile Strength, psi                                                                 9300                                                                               8,600                                                                              9,200                                                                               8000 9,100                                                                               9,800 9,500 9,200                 SI    Ultimate Tensile Strength, MPa                                                                 64.1                                                                               59.3                                                                               63.4 55.2 62.7 67.6  65.5  63.4                  US    Tensile Strength, Failure, psi                                                                 9100                                                                               9,200                                                                              9,200                                                                               9300 9,000                                                                               9,800 8,900 9,100                 SI    Tensile Strength, Failure, MPa                                                                 62.7                                                                               63.4                                                                               63.4 64.1 62   67.6  61.4  62.7                        Elongation, Yield %                                                                            8   9   5    8    9    8     8     8                           Ultimate Elongation %                                                                          105 40-105                                                                             110  100  100  114   25-118                                                                               100                   3 Days                                                                         (72 hours)                                                                     US    Tensile Strength at Yield, psi                                                                 9400                                                                               11,700                                                                             10,300                                                                              9500 9,800                                                                               9,000 --    --                    SI    Tensile Strength at Yield, MPa                                                                 64.81                                                                              80.7                                                                               71   65.5 67.6 62                                US    Ultimate Tensile Strength, psi                                                                 9400                                                                               11,700                                                                             10,700                                                                              9500 9,800                                                                               9,000 11,400                                                                               11,400                SI    Ultimate Tensile Strength, MPa                                                                 64.81                                                                              80.7                                                                               71   65.5 67.6 62    78.6  78.6                  US    Tensile Strength, Failure, psi                                                                 8000                                                                               10,500                                                                             7,000                                                                               8000 7,300                                                                               6,800 --    11,400                SI    Tensile Strength, Failure, MPa                                                                 55.2                                                                               72.4                                                                               53.8 55.2 50.3 46.9        78.6                        Elongation, Yield %                                                                            8   6   6    7    6    5     --    --                          Ultimate Elongation %                                                                          9-30                                                                               8   40-100                                                                              8-40 15-35                                                                               10-50 10    4                     6 Days                                                                         (144 hours)                                                                    US    Tensile Strength at Yield, psi                                                                 --  --  --   9600 10,200                                                                              9,200 --    --                    SI    Tensile Strength at Yield, MPa                                                                              66.2 70.3 63.4                              US    Ultimate Tensile Strength, psi                                                                 9400                                                                               12,300                                                                             9,500                                                                               9600 10,200                                                                              9,200 12,000                                                                               9,600                 SI    Ultimate Tensile Strength, MPa                                                                 64.81                                                                              84.8                                                                               65.5 66.2 70.3 63.4  82.7  66.2                  US    Tensile Strength, Failure, psi                                                                 9400                                                                               12,300                                                                             9,500                                                                               7100 8,400                                                                               6,600 --    9,600                 SI    Tensile Strength, Failure, MPa                                                                 64.81                                                                              84.8                                                                               65.5 49   58   45.5        66.2                        Elongation, Yield %                                                                            --  --  --   7    8    5     --    --                          Ultimate Elongation %                                                                          7   6   2    8-90 8-60 6     5     4                     12 Days                                                                        (288 hours)                                                                    US    Tensile Strength at Yield, psi                                                                 9300                                                                               --       --   10,200                                                                              10,000                                                                               --    --                    SI    Tensile Strength at Yield, MPa                                                                 64.1                                                     US    Ultimate Tensile Strength, psi                                                                 9100                                                                               10,600   9700 10,200                                                                              10,000                                                                               10,500                                                                               4,600                 SI    Ultimate Tensile Strength, MPa                                                                 62.7                                                                               73  Samples                                                                             66.9 70.3 69    72.4  3                     US    Tensile Strength, Failure, psi                                                                 9000                                                                               10,600                                                                             Cracked                                                                             9700 8,400                                                                               9,100 10,500                                                                               4,600                 SI    Tensile Strength, Failure, MPa                                                                 62  73       66.9 58   62.7  72.4  31.7                        Elongation, Yield %                                                                            8            --   5    8     --    --                          Ultimate Elongation %                                                                          7            6    5-80 6-12  3     3                     24 Days                                                                        (576 hours)                                                                    US    Tensile Strength at Yield, psi                                                                 --  --  --   9800 10,800                                                                              10,000                                                                               --    --                    SI    Tensile Strength at Yield, MPa                                                                              67.5 74.5 69                                US    Ultimate Tensile Strength, psi                                                                 9400                                                                               5,500                                                                              3,100                                                                               9800 10,800                                                                              10,000                                                                               4,700 1,200                 SI    Ultimate Tensile Strength, MPa                                                                 64.81                                                                              38  21   67.5 74.5       32    8.3                   US    Tensile Strength, Failure, psi                                                                 9400                                                                               5,500                                                                              3,100                                                                               9000 9,700                                                                               9,100 --    1,200                 SI    Tensile Strength, Failure, MPa                                                                 64.81                                                                              38  21   62   67   62.7        8.3                         Elongation, Yield %                                                                            5   2   --   6    5    5     --    --                          Ultimate Elongation %                                                                          --  --  1    1    8    6     1     1                     __________________________________________________________________________

                                      TABLE XI                                     __________________________________________________________________________     Dry Air Aged (130° C.) Tensile Properties of Polycarbonates             Compounded with Various Cadmium Salts                                          and Zinc Salts of Organic Acids                                                                     Cadmium-                  Cadmium                                              2-Ethyl-                                                                             Cadmium                                                                             Zinc Cadmium                                                                             Cadmium                                                                             Octoate/Phenyl                                                                            Cadmium              Aged Additive        Hexanoate                                                                            Octoate                                                                             Octoate                                                                             Laurate                                                                             Acetate                                                                             Diphenyl                                                                                  Stearateite          __________________________________________________________________________          Additive Wt. %  0.05  0.033                                                                               0.035                                                                               0.041                                                                               0.015                                                                               0.059/                                                                              0.177/                                                                               0.056                                                               0.041                                                                               0.152                      0 Days                                                                              Initial Tensile Properties                                                US   Tensile Strength at Yield, psi                                                                 9,300 9,300                                                                               9,000                                                                               9,300                                                                               9,100                                                                               9,200                                                                               9,200 9,300                SI   Tensile Strength at Yield, MPa                                                                 64.1  64.1 62   62   62.7 63.4 63.4  64.1                 US   Ultimate Tensile Strength, psi                                                                 9,300 8,600                                                                               9,200                                                                               9,300                                                                               9,100                                                                               9,800                                                                               9,500 9,200                SI   Ultimate Tensile Strength, MPa                                                                 63.4  59.3 63.4 64.1 62.7 67.6 65.5  63.4                 US   Tensile Strength, Failure, psi                                                                 9,100 9,700                                                                               9,200                                                                               9,000                                                                               9,000                                                                               9,800                                                                               8,900 9,100                SI   Tensile Strength, Failure, MPa                                                                 62.7  66.9 63.4 62   62   67.6 61.4  62.7                      Elongation, Yield %                                                                            8     9    5    8    9    8    8     8                         Ultimate Elongation %                                                                          105   40-105                                                                              110  100  100  114  25-118                                                                               105                  3 Days                                                                         US   Tensile Strength at Yield, psi                                                                 10,800                                                                               11,400                                                                              11,400                                                                              10,900                                                                              11,000                                                                              10,400                                                                              10,900                                                                               11,600               SI   Tensile Strength at Yield, MPa                                                                 74.5  78.6 78.6 75.1 75.8 71.7 75.1  80                   US   Ultimate Tensile Strength, psi                                                                 10,900                                                                               11,400                                                                              11,400                                                                              10,900                                                                              11,000                                                                              10,400                                                                              10,900                                                                               11,600               SI   Ultimate Tensile Strength, MPa                                                                 75.1  78.6 78.6 75.1 75.8 71.7 75.1  80                   US   Tensile Strength, Failure, psi                                                                 9,800 9,100                                                                               8,800                                                                               9,900                                                                               11,000                                                                              10,400                                                                              10,900                                                                               11,600               SI   Tensile Strength, Failure, MPa                                                                 67.6  62.7 60.7 68.3 75.8 71.7 75.1  80                        Elongation, Yield %                                                                            5     5    6    5    5    8    5     5                         Ultimate Elongation % 40-60     7-60 75-105                                                                              80-105                                                                              50-110                                                                               5-35                 6 Days                                                                         US   Tensile Strength at Yield, psi                                                                 10,300                                                                               10,800                                                                              10,600                                                                              10,300                                                                              10,600                                                                              10,600                                                                              11,200                                                                               10,600               SI   Tensile Strength at Yield, MPa                                                                 71.1  74.5 73.1 71.1 73.1 73.1 77.2  73.1                 US   Ultimate Tensile Strength, psi                                                                 10,300                                                                               10,800                                                                              10,700                                                                              10,300                                                                              10,300                                                                              10,600                                                                              11,200                                                                               9,700                SI   Ultimate Tensile Strength, MPa                                                                 73.1  74.5 73.8 71.1 71.1 73.1 77.2  66.9                 US   Tensile Strength, Failure, psi                                                                 8,600 7,800                                                                               9,700                                                                               7,600                                                                               8,300                                                                               8,000                                                                               7,600 8,600                SI   Tensile Strength, Failure, MPa                                                                 59.3  53.8 66.9 52.4 57.2 55.2 52.4  59.3                      Elongation, Yield %                                                                            8     7    4    6    4    10   5     4                         Ultimate Elongation %                                                                          100             7-25 7-20 60-115                                                                              5-70  2-7                  12 Days                                                                             Tensile Strength at Yield, psi                                                                 11,000                                                                               11,000                                                                              --   11,000                                                                              12,200                                                                              11,400                                                                              --    --                        Tensile Strength at Yield, MPa                                                                 75.8  75.8 --   75.8 84.1 78.6 --    --                        Ultimate Tensile Strength, psi                                                                 11,000                                                                               11,800                                                                              6,000                                                                               11,000                                                                              11,200                                                                              11,400                                                                              10,600                                                                               --                        Ultimate Tensile Strength, MPa                                                                 75.8  81.4 41.4 75.8 77.2 78.6 73.1  --                        Tensile Strength, Failure, psi                                                                 10,000                                                                               11,800                                                                              6,000                                                                               9,900                                                                               10,000                                                                              9,100                                                                               10,600                                                                               --                        Tensile Strength, Failure, MPa                                                                 70    81.4 41.4 68.3 70   62.7 73.1  --                        Elongation, Yield %                                                                            10    10   --   10   5    8    --    --                        Ultimate Elongation %                                                                          10-100                                                                               10   2    10-55                                                                               5-15 10-75                                                                               6     --                   24 Days                                                                             Tensile Strength at Yield, psi                                                                 --    --   --   --   10,700                                                                              11,300                                                                              --    --                        Ultimate Tensile Strength, psi                                                                 9,700 3,900                                                                               1,050                                                                               9,800                                                                               10,700                                                                              11,300                                                                              Samples                                                                              2,700                     Tensile Strength, Failure, psi                                                                 9,800 3,900                                                                               1,050                                                                               9,800                                                                               8,500                                                                               10,100                                                                              degraded                                                                             2,700                     Elongation, Yield %                  6    5    totally                         Ultimate Elongation %                                                                          6                    12   10                              __________________________________________________________________________

                                      TABLE XII                                    __________________________________________________________________________     COLOR RETENTION AT 550°  F. AND 700° F. MOLDINGS AS WELL AS      AGING PROPERTIES                                                                                                          OVEN AGED AT 130° C.                                    550° F.                                                                       700° F.                                                                           6 days 12 days                                                                              24 days                                       Wt %                                                                               Y %                                                                               YI Y % YI    Y % YI Y %                                                                               YI Y                      __________________________________________________________________________                                                                 % YI                                                                           .                  Cadmiun 2-ethylhexanoate                                                                              0.05                                                                               88.23                                                                             3.3                                                                               88.26                                                                              3.3   88.39                                                                              4.9                                                                               87.17                                                                             10.4                                                                              88.06                                                                              6.0                                           88.47                                                                             3.6                                                                               88.52                                                                              4.0   88.02                                                                              4.1                                                                               88.37                                                                             4.1                                                                               88.26                                                                              4.5                Cadmium Laurate        0.042                                                                              88.01                                                                             3.7                                                                               87.77                                                                              6.4   88.11                                                                              5.2                                                                               -- -- 87.91                                                                              6.3                Cadmium                    88.16                                                                             4.4                                                                               88.17                                                                              5.9   87.64                                                                              5.0                                                                               87.86                                                                             5.0                                                                               87.45                                                                              5.6                Cadmium Octoate        0.033                                                                              87.72                                                                             6.3                                                                               59.11                                                                              15.1  87.35                                                                              9.0                                                                               86.05                                                                             11.2                                                                              85.93                                                                              12.3                                          88.55                                                                             7.4                                                                               55.26*                                                                             61.6  87.81                                                                              9.1                                                                               86.81                                                                             11.2                                                                              85.82                                                                              14.9               Cadmium Stearate       0.056                                                                              88.46                                                                             9.4                                                                               42.91                                                                              13.4   Not aged since specimens show                                                 a high                                                                         discoloration at 550°                                                   F. and 700° F.                                                          molding.                            Cadmium Acetate        0.015                                                                              88.03                                                                             4.6                                                                               69.70                                                                              15.2  --  -- -- -- 87.73                                                                              7.4                Zinc Octoate           0.035                                                                              88.74                                                                             5.2                                                                               70.23                                                                              46.9  87.33                                                                              5.8                                                                               87.93                                                                             6.5                                                                               86.06                                                                              14.0               Cadmium Valerate       0.026                                                                              87.60                                                                             5.2                                                                               63.89                                                                              33.8  Since these compositions did                                                   not exhibit                         Cadmium Palmitate      0.052                                                                              87.83                                                                             8.3                                                                               63.76                                                                              41.4  retention of impact properties                                                 during oven                         Cadmium Myristate      0.047                                                                              87.86                                                                             7.5                                                                               65.38                                                                              33.2  and water aging, the optical                                                   property aging                      Cadmium Octoate/phenyl diphenyl phosphinite                                                           0.059/                                                                             88.77                                                                             4.98                                                                              61.63*                                                                             48.96*                                                                               studies were not evaluated.                                0.041                                                                              --  --                                                                                -- --    87.80                                                                              4.62                                                                              88.07                                                                             4.5                                                                               87.24                                                                              5.7                Cadmium Octoate/phenyl diphenyl phosphinite                                                           0.177/                                                                             82.47                                                                              68                                                                               (degraded)                                                           0.123                                                                              --  --                                                                                -- --    76.93                                                                              9.10                                                                              76.70                                                                             8.2                                                                               74.27                                                                              13.7               __________________________________________________________________________      *Exhibited splaying                                                            700° F. molding with 1 min                                              550° F. molding with 35 secs cycle                                

From a review of the data of Tables VIII-XII, it can be noted that while several of the additives do, in fact, impart equivalent and at times superior properties to the polycarbonate composition in some tests than do the instantly claimed cadmium salts, only the instantly claimed polycarbonates containing cadmium 2-ethylhexanoate, cadmium octoate, cadmium laurate and cadmium acetate exhibit the best overall combination of tensile, impact and optical properties.

Although the invention has been described with reference to specific materials, the scope of the invention is only to be limited as is set forth in the accompanying claims. 

What is claimed is:
 1. A halogen-free moldable aromatic polycarbonate comprising:(a) an aromatic polycarbonate resin; and (b) a cadmium salt of an organic acid selected from the group consisting of cadmium 2-ethylhexanoate and cadmium laurate,characterized in that said salt is present in said polycarbonate resin in an amount between 0.01 to 0.1% by weight based on the weight of said polycarbonate resin.
 2. The polycarbonate of claim 1, wherein said cadmium salt is cadmium 2-ethylhexanoate.
 3. The polycarbonate of claim 1, wherein said cadmium salt is cadmium laurate.
 4. A moldable aromatic polycarbonate consisting essentially of:(a) an aromatic polycarbonate resin; and (b) a cadmium salt of an organic acid selected from the group consisting of cadmium 2-ethylhexanoate,characterized in that said salt is soluble in said polycarbonate resin and present in an amount between 0.01 to 0.1% by weight based on the weight of said polycarbonate resin.
 5. A moldable aromatic polycarbonate having no phosphorous containing stabilizers comprising:an aromatic polycarbonate resin; and cadmium 2-ethylhexanoate,characterized in that cadmium 2-ethylhexanoate is present in an amount between 0.01 to 0.1% by weight based on the weight of said polycarbonate resin. 